Fan assembly and heat dissipation device having the same

ABSTRACT

A heat dissipation device includes a heat sink, a fan mounted on a top side of the heat sink and a fan holder connecting the heat sink with the fan. The fan includes a blade assembly and a frame enclosing the blade assembly. The fan holder includes a supporting portion engaging with the heat sink. A connecting plate extends upwardly from an edge of the supporting portion. A ridge extends angulately and downwardly from an inner surface of the connecting plate. An operating plate extends downwardly from a bottom end of the connecting plate. The operating plate is pressed inwardly or pulled outwardly to make the ridge of the connecting plate space from or engage with the frame of the fan.

BACKGROUND

1. Technical Field

The present invention relates to heat dissipation devices and,particularly, to a fan assembly capable of being conveniently assembledto and disassembled from a heat sink, and a heat dissipation devicehaving such a fan assembly and a heat sink.

2. Description of Related Art

A heat sink is usually placed in thermal contact with a heat generatingelectronic device such as a central processing unit (CPU), and transfersheat through conduction away from the heat generating electronic deviceso as to prevent over-heating of the heat generating electronic device.

Typically, a fan is mounted on a side of a heat sink by a fan holder toimprove heat dissipation efficiency of the heat sink. The fan comprisesa blade assembly and a frame enclosing the blade assembly. Diagonallycorners of the frame define two mounting holes, respectively. Twoelastic pins extend upwardly from diagonally corners of the fan holderand corresponds to the mounting holes of the frame. The elastic pins ofthe fan holder are pressed into the mounting holes of the frame. Whenthe elastic pins extend through the mounting holes, the elastic pinsexpand and firmly contacts the frame. In that state, the fan and the fanholder are assembled together. However, it is difficult to disassemblethe fan from the fan holder, and technical tools may be used. This isvery time-consuming and trouble.

For the foregoing reasons, there is a need in the art for a heatdissipation device which can overcome the limitations described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembled view of a heat dissipation device in accordancewith an embodiment of the present disclosure, in which the heatdissipation device is mounted on a printed circuit board.

FIG. 2 is an exploded view of the heat dissipation device in FIG. 1.

FIG. 3 is an inverted view of FIG. 2.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, an embodiment of a heat dissipation devicecomprises a heat sink 20, a fan 40 mounted on a top side of the heatsink 20 and a fan holder 30 connecting the heat sink 20 with the fan 40.

Referring to FIG. 3 also, the heat sink 20 comprises a cylindrical heatabsorbing portion 21, a number of first fins 23 and a number of secondfins 24 extending outwardly and radially from a periphery of the heatabsorbing portion 21. The first fins 23 are divided into four groupswhich are equidistantly spaced from each other and oriented towarddifferent directions by four mounting arms 26 extending evenly from theperiphery of the heat absorbing portion 21. Each of the first fins 23comprises an elongated first connecting plate 231 connected the heatabsorbing portion 21 and two elongated and angled first extending plates233 extending outwardly from the outmost end of the first connectingplate 231. The second fins 24 are divided into four groups also. Eachgroup of the second fins 24 comprises two adjacent second fins 24positioned between the two adjacent groups of the first fins 23. Eachsecond fin 24 comprises an elongated second connecting plate 241extending from the heat absorbing portion 21 and two elongated andangled second extending plates 243 extending outwardly from the outmostend of the second connecting plate 241. A height of the first connectingplate 231 is equal to that of the second connecting plate 241. Heightsof the first and second extending plates 233, 243 are less than that ofthe heat absorbing portion 21. A width of the first connecting plate 231is equal to that of the second connecting plate 241. A width of thefirst extending plate 233 is larger than that of the second extendingplate 243. Tops of the first and second fins 23, 24 and a top surface ofthe heat absorbing portion 21 are coplanar. The bottom portion of theheat absorbing portion 21 is below bottom ends of the first and secondfins 23, 24; thus a step 25 is defined at a bottom portion of the heatsink 20.

A height of the mounting arm 26 is equal to that of the first fin 23. Awidth of the mounting arm 26 is equal to that of the first fin 23. Athickness of the mounting arm 26 is larger than that of the first andsecond fins 23, 24. Each of the mounting arms 26 is sandwiched betweenthe two adjoining second fins 24. An inner section of the mounting arm26 and the second connecting plates 241 of the two adjoining second fins24 are integrated, and an outer section of the mounting arm 26 is spacedfrom the second connecting plates 241 of the two adjoining second fins24. An outmost end of the mounting arm 26 defines two spaced firstengaging portions 261 to engage with the fan holder 30 and a secondengaging portion 263 to engage with a printed circuit board 10. Each ofthe first engaging portions 261 is an elongated groove and extends alonga height direction of the mounting arm 26. The eight first engagingportions 261 are divided into first and second groups. The firstengaging portions 261, which are located at front sides of the mountingarms 26, respectively, along a clockwise direction as viewed from FIG.2, belong to the first group. The first engaging portions 261, which arelocated at rear sides of the mounting arms 26, respectively, belong tothe second group. The first and second groups of the first engagingportions 261 are engage with the fan holder 30. The second engagingportion 263 is positioned between the two first engaging portions 261and has a C-shaped configuration. Four screws 50 extend through thesecond engaging portions 263 and engage with the printed circuit board10 to mount the heat sink 20 on the printed circuit board 10.

The fan holder 30 is integrally formed by a plastic material andcomprises an annular engaging member 31 and four supporting portions 33extending outwardly from a top end of the engaging member 31. The foursupporting portions 33 are equidistantly spaced from each other. The twoadjacent supporting portions 33 are connected by a linking plate 35which extends inwardly from an edge of the engaging member 31. Thesupporting portion 33 is a triangular plate and is beyond the engagingmember 31. A connecting plate 331 extends upwardly from an edge of thesupporting portion 33. A ridge 3312 extends angulately and downwardlyfrom a top end of the connecting plate 331 to press the fan 40. Anoperating plate 333 extends downwardly from a bottom end of theconnecting plate 331. The connecting plate 331, the operating plate 333and the ridge 3312 are integrally made of elastic material. Theoperating plate 333 is pressed inwardly or pulled outwardly to make theridge 3312 of the connecting plate 331 space from or engage with the fan40. A through hole 332 is defined in the supporting portion 33 and isadjacent to a joint of the supporting portion 33 and the connectingplate 331. An elastic pin 335 extends upwardly from a top surface of thesupporting portion 31 and is located at an outer side of the connectingplate 331. The pins 335 engage with the fan 40. A screw hole 339 isdefined at a corner of the supporting portion 33. Four screws 60 extendthrough the screw holes 339 and engage with the first or second group ofthe first engaging portions 261 of the four mounting arms 26 of the heatsink 20 to mount the fan holder 30 on the heat sink 20. A triangularreinforcing rib 337 is formed at a bottom surface of the supportingportion 33 and connects with the engaging member 31.

The fan 40 comprises a cubical bracket 41 and a blade assembly 43received in the bracket 41. Central portions of four corners of thebracket 41 are recessed; thus, four triangular mounting portions 412 areformed at bottom end of the bracket 41. Central portion of the mountingportion 412 defines a through hole 414 to receive the pin 335 of the fanholder 30.

In assembly, the screws 50 extend through the second engaging portions263 of the mounting arms 26 of the heat sink 20 and engage with theprinted circuit board 10 to mount the heat sink 20 on the printedcircuit board 10. The engaging member 31 of the fan holder 30 encloses atop end of the heat sink 20 and the screw hole 339 of the supportingportion 33 aligns with the corresponding first engaging portion 261 ofthe mounting arm 26. The screws 60 extend through the screw holes 339and engage with the first or second groups of the first engaging portion261 to mount the fan holder 30 on the heat sink 20. The operating plates333 of the fan holder 30 are subjected to an external force, whichpresses the operating plates 333 inwardly to make the connecting plates331 run outwardly. Thereafter, the fan 40 is pressed towards the fanholder 30 until the pins 335 of the fan holder 30 extend in the throughholes 414 of the mounting portions 412. Then, the external force of theoperating plates 333 is released; a resilience of the operating plates333 impels the connecting plates 331 to move towards the fan 40. As aresult, the ridges 3312 of the connecting plates 331 press the topsurfaces of the supporting portions 33. Therefore, the heat dissipationdevice is assembled completely.

In disassembly, the operating plates 333 are pressed inwardly to makethe connecting plates 331 run outwardly until the ridges 3312 of theconnecting plates 331 are separated from the supporting portions 33.Thereafter, the fan 40 is taken out from the fan holder 30. Thus, thefan 40 is disassembled from the fan holder 30.

It is to be understood, however, that even though numerouscharacteristics and advantages of the disclosure have been set forth inthe foregoing description, together with details of the structure andfunction of the disclosure, the disclosure is illustrative only, andchanges may be made in detail, especially in matters of shape, size, andarrangement of parts within the principles of the disclosure to the fullextent indicated by the broad general meaning of the terms in which theappended claims are expressed.

1. A fan assembly comprising: a fan comprising a blade assembly and aframe supporting the blade assembly; and a fan holder comprising asupporting portion, a connecting plate extending upwardly from an edgeof the supporting portion, a ridge extending angulately and downwardlyfrom a top end of the connecting plate, an operating plate extendingdownwardly from a bottom end of the connecting plate; wherein theoperating plate is pressed inwardly or pulled outwardly to make theridge of the connecting plate space from or engage with the frame of thefan.
 2. The fan assembly as claimed in claim 1, wherein the connectingplate and the operating plate are integrally made of an elasticmaterial.
 3. The fan assembly as claimed in claim 1, wherein a pinextends upwardly from a top surface of the supporting portion andextends through the frame of the fan.
 4. The fan assembly as claimed inclaim 1, wherein an engaging member connects with the supportingportion, the engaging member adapted for engaging with a heat sink. 5.The fan assembly as claimed in claim 4, wherein the engaging member isannular and the supporting portion extends outwardly from a top of theengaging member.
 6. The fan assembly as claimed in claim 5, wherein areinforcing rib is formed at a bottom of the supporting portion andconnects with the engaging member.
 7. The fan assembly as claimed inclaim 5, wherein a plurality of supporting portions are formed at thetop of the engaging member.
 8. The fan assembly as claimed in claim 1,wherein a through hole is defined in the supporting portion and isadjacent to a joint of the supporting portion and the connecting plate.9. A heat dissipation device comprising: a heat sink; a fan mounted on atop side of the heat sink, the fan comprising a blade assembly and aframe enclosing the blade assembly; and a fan holder comprising asupporting portion engaging with the heat sink, a connecting plateextending upwardly from an edge of the supporting portion, a ridgeextending angulately and downwardly from a top end of the connectingplate, an operating plate extending downwardly from a bottom end of theconnecting plate; wherein the operating plate is pressed inwardly orpulled outwardly to make the ridge of the connecting plate space from orengage with the frame of the fan.
 10. The heat dissipation device asclaimed in claim 9, wherein a pin extends upwardly from a top surface ofthe supporting portion and through the frame of the fan.
 11. The heatdissipation device as claimed in claim 10, wherein an engaging memberconnects with the supporting portion, and the engaging member encloses atop end of the heat sink therein.
 12. The heat dissipation device asclaimed in claim 9, wherein the heat sink comprises a heat absorbingportion and a plurality of mounting arms extending outwardly andradially from a periphery of the heat absorbing portion, a screw extendsthrough the supporting portion of the fan holder and engages with acorresponding mounting arm to mount the fan holder on the heat sink. 13.The heat dissipation device as claimed in claim 12, wherein the heatsink comprises a plurality of fins extending outwardly and radially froma periphery of the heat absorbing portion, and a bottom end of the heatabsorbing portion is below bottom ends of the fins.
 14. The heatdissipation device as claimed in claim 13, wherein each of the finscomprises a connecting plate connected the heat absorbing portion andtwo angled extending plates extending outwardly from an outmost end ofthe connecting plate.
 15. The heat dissipation device as claimed inclaim 14, wherein the fins are divided a plurality of groups and eachgroup of the fins is sandwiched between two adjacent mounting arms.